Cartridge-type spring-bias means for a predetermined torque release wrench



.United States Patent i.

3,018,677 CARTRIDGE-TYPE SPRING-BIAS MEANS FOR A PREDETERMINED TORQUE RELEASE WRENCH Peter J. Mutolo, Buffalo, and Eric G. Boehm, Orchard Park, N.Y., assignors to Houdaille Industries, Inc.,

Buialo, N.Y., a corporation of New York Filed Mar. 8, 1960, Ser. No. 13,575

4 Claims. (Cl. 81-52.4)

This invention relates to torque indicating wrenches such as are arranged to impart audible and tactile signals to the operator thereof when the desired torque limit has been reached and more particularly to a preset replaceable spring cartridge therefor.

The spring cartridge of the present invention is herein described as being utilized in conjunction with a torque indicating wrenchwhich is arranged to impart an audible and taetilersignal to the operator when 4a desired torque setting has been reached although it might nd utility in many other structures other than torque wrenches and, in fact, in various types of torque applying tools.

Basically, torque wrenches generally 'are constructed in substantially the following manner: the torque wrench includes a hollow housing orv handle which hasv a tool part pivotally mounted therein which is adapted to receive a tool on the outer end thereof, such as `an open endedor crescent wrench. A reaction block is mounted yfor axial movement within :thehandle housing and means pivotally 'interconnect the adjacent ends of the block and the tool part so that when a predetermined torque has been applied to the workpiece through the torque wrench handle, the inner end of the tool part will move `from one pivoted position to another. The block is biased toward the innermost end of the tool part by -a compression spring having one end -seated on the block and having its opposite end seated against van end of the handle housing. Otten, means are provided at one end of the handle housing to adjust the load of the compression spring so that the wrench can be adjusted to 'break at diierent torque y values.

It will be understood that torque wrenches of the type above described are often employed by mechanics in garages or in assembly plants who need wrenches having `only two or three different torque settings when working on a given job. When torque wrenches were rst employed, of course, the need for torque wrench tools havling two ory three Yditlerent torque settings necessitated the provision of as many torque wrenches inasmuch as no means was provided for adjusting the compression of the spring within the wrench. Subsequently however -developments were made in torque wrenches and means the operator which would be effective to provide a plurality of different torque settings.

The use of adjustable torque wrenches, however, made l it necessary for the operator thereof to continually adjust and readjust the torque setting of the wrench -as he moved from one job to another.

We have designed `a self-contained preset replaceable spring cartridge which may initially be adjusted by the operator or at the tfactory to a desirable torque setting and which may thereupon be inserted into a handle housing of a torque wrench to provide a desired torque setting. A number of spring cartridges might be utilized by the operator of the wrench which are preset with different spring loads, and the handle housing of the wrench is provided with means whereby the cartridge may readily be inserted and removed therefrom.

The use of such self-contained preset replaceable spring cartridges in torque Wrenches obviates the necessity of 3,0l877 Patented Jan. 30, 1962 having to carefully readjust the torque setting of the torque wrench whenever a different torque setting is desired and may often decrease the time necessitated in changing the torque values of the torque wrench, particularly where the torque settings are very critical.

Such self-contained preset spring cartridges may, of course, have utility in combination with other structures than torque wrenches, but since they have particular utility with torque wrenches they have been described as being so employed herein.

The torque wrench which is illustrated in the appended drawings now employs such a preset replaceable spring cartridge and has means provided therein for preventing the reaction block from moving out of its proper position within the handle housing upon removal of the spring cartridge. It such a means were not provided, the interior components of the -torque wrench might become disassembled upon removal of the spring cartridge.

An adjusting screw is provided in one end of the spring cartridge with which the spring load of the cartridge may be adjusted, but a wax or lead seal may 4be formed over the adjusting screw so that once the desired spring load has been determined by adjustment of the screw, further movement thereof will |be prevented.

=It is therefore a principal object of the present invention to provide a torque indicating wrench employing a self-contained preset spring cartridge which may be readily inserted and removed from the handle housing of the torque wrench.

Another object of the invention resides in the provision of a self-contained spring cartridge having a cylindrical casing and having a movable wall member at one end thereof which is biased toward the outer end of the casing by a compression spring but which is prevented from moving out of the casing by a conning lip.

A further object of the invention is the provision of a torque indicating wrench of the type above described and employing a self-contained preset replaceable spring cartridge, wherein the reaction block has abutment means associated therewith which limit the degree of axial movement thereof within the wrench handle,

These and other objects of the invention will appear from time to time as the following speciication proceeds and with reference to the accompanying drawings, wherein:

FIGURE 1 is a vertical sectional View through a torque Wrench constructed in accordance with the principles of the present invention and employing a self-contained preset replaceable spring cartridge;

FIGURE 2 is a fragmental vertical sectional view which is similar in nature to FIGURE 1 but which shows the various components of the wrench in a broken position;

FIGURE 3 is a vertical sectional view of the torque wrench which is similar in nature to FIGURE l but which shows the wrench when the spring cartridge is re- 'moved and the end cap is oi; and

IFIGURE 4 is a fragmental vertical sectional View of a second embodiment of our invention.

Referring initially to FIGURE 1, a torque wrench 10 includes a housing 11 having a generally cylindrical inner bore 12 within which a reaction block 13 is mounted for axial sliding movement.

A tool part 14 has one end disposed within the housing 11 and is pivotally mounted by means of a pin 15 in the housing. The outermost end of the tool part 14 has engagement means 16 formed thereon which are adapted to serve as a means for mounting a tool such as an open ended or crescent wrench 17 thereon.

The innermost end of the tool part 14 is formed in the configuration of a clevis, as at 18, across which a pin 19 is mounted. A cylindrical bearing 20 is tted about the pin 19 and is adapted to move rotatably. The outermost end of the reaction block 13 is similarly formed in the configuration of a clevis, as at 22, and has a pin 23 mounted thereacross and spaced radially outwardly of the center axis of the bore 12, upon which, in turn, a three-lobed cam 24 is mounted.

The three-lobed cam 24 is adapted to receive the bearing within the `depression 24a opposite the lobe of the cam which is mounted on the pin 23.

Assuming that means resiliently bias the reaction block 13 toward the tool part 14, the torque wrench will function in the following manner to impart an audible and tactile signal fo the operator thereof when the desired torque has been reached: when the wrench is gripped and pulled in the direction of the arrow, the parts will normally remain in the position illustrated in FIGURE l until a predeterimned torque has been applied, at which time, the force applied by the bearing 20 on the inner end of the tool part 14 against the cam 24 will be suficient to cause compression of the spring means biasing the reaction block 13 toward the tool part 14. At such time the reaction block 13 will back off slightly and the tool part 14 and cam 24 will pivot to the positions illustrated in FIGURE 2. vMovement of one of the cam lobes and the inner end portion of the tool part 14 into engagement with the wall of the bore 12 will impart a shock load to the handle to give the operator thereof a tactile signal while at the same time such movement of these parts will create a sufficient sound to audibly indicate to the operator that the desired torque has been reached.

The means for biasing the reaction block 13 toward the innermost end of the tool part 14 consists of a selfcontained preset spring cartridge which comprises generally a cylindrical casing 31 having a pair of wall members 32 and 33 slidably mounted for axial movement therein which are interconnected by means of a compression spring 34. A spring retainer 35 is mounted adjacent one end of the casing 31 within an annular groove formed in the inner wall of the casing 31 which provides a lip preventing movement of the wall member 32 exteriorly of the casing 31.

A helically threaded adjusting screw 37 is threadedly mounted in the opposite end of the casing 31 having its inner end disposed in engagement with the wall member 33; the relative axial position of the screw 37 within the casing 31 determining the position of the wall member 33 and thereby determining the spring load of the compression spring 34. A wax seal is formed over the outermost end of the adjusting screw 37 which is adapted to prevent unauthorized persons from tampering with the setting of the screw 37 or to prevent accidental movement thereof.

It will be apparent from the foregoing that the cartridge 30 comprises a self-contained preset spring cartridge which may be employed for a variety of purposes in many different structures.

In the present instance the spring cartridge 30 is adapted to be fitted within the bore 12 of the housing 11 with its inner most end abutting a shoulder 40 of the bore 12 which faces toward the end of the handle opposite the tool part 14. Subsequent to the insertion of the cartridge 30 within the bore 12, an end cap 41 is threadedly mounted on the end of the housing 11 which serves to hold the cartridge 30 within its proper position in the bore 12.

The reaction block 13 has an outwardly extending portion 43 which has a diameter considerably smaller than the inner diameter of the ring 35 so that the end portion 43 will always be maintained in juxtaposition with the outer surface of the wall member 32.

In order to prevent accidental disassembly of the various components of the torque wrench upon removal of the cartridge 30, a pin 45 extends radially inwardly of the side wall of the bore 12 at a point intermediate the radially enlarged portion 46 of the reaction block 13 and the shoulder 40, so that even when the spring cartridge 30 is removed from the bore 12 the degree of axial movement of the reaction block 13 will be limited so that the block and its associated components will not accidentally be removed at the same time.

In the embodiment of the invention illustrated in FIGURE 4, a retaining ring 50 is fitted within the bore 12 at the open end thereof which serves to prevent the wall member 33 from moving out of the bore. A reaction block 51 has a shank 52 which fits through the ring 50 and which abuts the wall member 33. The reaction block 51 has its head seated on a spacer 53 which fits within the bore 12 and abuts the end cap 41. It will be observed from the foregoing that by substituting spacers having different thicknesses the spring load of the spring cartridge can readily be varied. Removal of the end cap will not result in disassemblage of the wrench 10 since the retaining ring 50 will serve to hold the spring 34 and its associated components Within the bore 12.

It will be understood that these embodiments of the invention have been used for illustrative purposes only and that various modifications and variations in the present invention may be effected without departing from n the spirit and scope of the novel concepts thereof.

We claim as our invention:

1. In a torque wrench including a housing having a tool part pivotally mounted therein `and having a block mounted for axial movement therein, means pivotally interconnecting adjacent ends of said block and said part, the improvement of replaceable means for biasing said block toward said part comprising a casing insertable within said housing, an axially movable seat disposed within said casing adjacent one end thereof and abutting said block, containing means confining said seat within said casing, and means within said casing biasing said seat toward said one end of said casing.

2. In a torque wrench including a housing having a tool part pivotally mounted therein and having a block mounted for axial movement therein, means pivotally interconnecting adjacent ends of said block and said part, the improvement of replaceable means for biasing said block toward said part comprising a casing insertable Within said housing, an axially movable seat disposed Within said casing adjacent one end thereof and abutting said block, containing means confining said seat within said casing, means within said casing biasing said seat toward said one end of said casing, and means mounted on said housing limiting the extent of axial movement of said block therein.

3. In a torque wrench including a housing having a tool part pivotally mounted therein and having a block mounted for axial movement therein, means pivotally interconnecting adjacent ends of said block and said part, the improvement of replaceable means for biasing said block toward said part comprising a casing insertable within said housing, axially movable seats disposed within said casing adjacent each end thereof, containing means confining said `seats within said casing, spring means Within said casing between said seats biasing said seats toward opposite ends thereof, means capping said housing which is fastened to said housing, and spacing means insertable between said capping means and one of said seats for determining the spring load of said spring means.

4. In a torque Wrench including a housing having a tool part pivotally mounted therein and having a block mounted for axial movement therein, means pivotally interconnecting adjacent ends of said block and said part, the improvement of replaceable means for biasing said block toward said part comprising a casing insertable within said housing, axially movable seats disposed within said casing adjacent each end thereof, containing means confining said seats within said casing, spring means within said casing between said seats biasing said seats 5 6 toward opposite ends thereof, means capping said housing References Cited in the le of this patent which is fastened to said housing, separate spacing means UNITED STATES PATENTS insertable between said capping means and one of said seats for determining the spring load of said spring means, gfoms l let' 129' and means within said hosing limiting the extent of axial 5 oswor c 

